We have one well feeding a house and a church building. The pressure tank is in the basement of the house. It is then piped to the church. When a toilet in the church is flushed, the pressure in the second floor bathroom of the house drops to near zero. Can we install a second pressure tank in the house basement for the church? If not, how can we solve the problem without digging another well?

Describe you piping. It is most likely that the piping to the church is tied into the piping to the second floor and the piping between that point and the tank is under sized.

I would add a large pressure tank in the church itself. This should take care of your problem. Good luck and please let us know what you think. Lee.

To hkstroud, piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building. The pressure tank is a Well Mate model WM14-WB, max operating pressure 125 psi, factory precharge 40 psig. A local plumber said we could not put a second pressure tank in the basement for the church building, but I couldn't understand his explanation of why.

Thwe plumber was concerned that you had combiuned the two systems.
Where you made your mistake was in not taking the church supply off before the house. I would move the church supply back before the house supply and install a check valve just upstream from it to isolate the house. Now your house is a closed system and you can treat the church as a new installation complete with check valve and bladder tank.
Bet your plumber likes this configuration better. Good luck, Tom

What is the pipe size between the tank and the point where the church is tied in, what is the house pipe size after that point and what is the pipe size to the church. Either the pipe to the split is inadequate or the water softener or the sterilizer is creating a flow restriction. Suggest bypassing the water softener just to see what happens. Do you need the water softener and sterilizer for the church? I see no reason why you couldn't have a second tank at the church. An additional tank at the church with a check valve should act just like a separate well and tank.

An additional tank at the church with a check valve should act just like a separate well and tank.
True that Herold! But only if it's taken off before the house system. Otherwise you'll be combining two systems and that's what the plumber was complaining about. To do it any other way would be making the house and church one system. Look at it this way. Leave the church supply the way it is and you're supplying the church from the house. Move the supply ahead of the house takeoff and you're supplying from the pump. Make better sense now? Tom

If he splits off to the church before the house, he will have to add another ultraviolet unit at the church, won't he?

Why not go: well to house to ultraviolet unit, then split to the house and church and put a tank/check valve in each location. The two systems would be separate from each other but still benefit from the sterilizer.

The problem I see with two tank/check valve setups is setting up the switch to the pump. Which tank pressure is going to turn the pump off/on? Can two switches be used for one pump?

Why not go: well to house to ultraviolet unit, then split to the house and church and put a tank/check valve in each location. The two systems would be separate from each other but still benefit from the sterilizer.
Works for me! But you're piling on a lot of labor and hassle. Did you read where le laid out the placement of the ultraviolet unit? What was that necessary for again? Tom

To hkstroud, piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building. The pressure tank is a Well Mate model WM14-WB, max operating pressure 125 psi, factory precharge 40 psig. A local plumber said we could not put a second pressure tank in the basement for the church building, but I couldn't understand his explaination of why.

Cavitation in the line between the two is the reason why.

The drop in pressure could likely be reduced if you installed a booster pump at the main line coming into the last leg of the system.

OK, what wrong with my logic?

Well pump supplies house tank. House tank supplies church tank and house. Pump runs until house tank reaches cut off. At that time both tanks are at cut off pressure. Water usage in the house does not affect church tank because of check valve.

Water usage in the church does not affect house unless church tank pressure drops below house tank pressure. Because of the presumably greater usage in the house and the cycling of the pump to replenish the house tank, the church tank will be at pump cut off pressure a good percentage of the time. When and if church tank drops below the house tank pressure there will of course be a flow from the house to the church, but that flow would be at a minimum because of the small pressure differential between the two tanks. Should there be a demand for water at the house as the two tank pressures are equalizing the reduction in flow to the house would be at a minimum.

Where did I miss the gate here.

Rereading Waterboy's post, note that he said this occurs on the second floor bath, didn't say entire house.

Think we should have asked at what pressures he is operating and what the size of the tank is.

Also should ask, does this happen all the time or just when tank is at or near cut in pressure or when operating on pump pressure only. Could be that he only needs a higher cut in pressure to minimize occurrence.

SB, he said: "piping: From the well, 103 feet to house, 33 feet across basenent to pressure tank, to an ultra violet sterilizer, to a water softener, then one pipe to the rest of the house and one pipe 75 feet to the church building."

You then suggested: "Where you made your mistake was in not taking the church supply off before the house. I would move the church supply back before the house supply and install a check valve just upstream from it to isolate the house."

So, if the UV unit is after the pressure tank, and you tell him to come off the main line (to go to the church) BEFORE it gets to the house, then how is the UV unit going to treat the water going to the church?

Harold, you asked why this wouldn't work
Well pump supplies house tank. House tank supplies church tank and house. That's why. Two bladder tanks on one system. Widdershins addressed that in a earlier postand the plumber refused to install it that way. You're insisting on making this one system and that's not going to fly.

Ron, If you're determined to include the house UV unit in the church system then you'll have to reconfigure the house system since both the UV and the softener are upstream from the house bladder tank. Both of you guys seem determined to combine the two systems and that's what got the nplunber uptightin the first place.
If you took off the church just upstream from the UV unit as you indicate the we would be back to two bladder tanks on the church line. About the only wayto use the UV unit for both ssystems would be to move the UV unit back downstream from the two check valves and just upstream from the pump. That way by having the pump and the UV unit ahead of where the two systems separated ,and they're going to hafta be separate to operate correctly, the pump would supply pressure and volume along with UV protection. Regards, Tom

Rereading Waterboy's post, note that he said this occurs on the second floor bath, didn't say entire house.

Think we should have asked at what pressures he is operating and what the size of the tank is.

Also should ask, does this happen all the time or just when tank is at or near cut in pressure or when operating on pump pressure only. Could be that he only needs a higher cut in pressure to minimize occurrence.



I agree 100% Harold. Great thinking. Maybe we should be looking at simple solutions to this instead of redesigning the complete layout. Upping cut in pressure(and or cut out pressure) or installing a larger pressure tank may be just what the doctor ordered.

What am I missing here guys? Ya-all seem to think that leaving the church takeoff ahead of everything else would be just peachy keen if only you installed a check valve. That's not going to fly. The plumber refused to install a bladdrer tank in the church, Growler gave you the reason for it and what else do you need? The way it's set up now the church is being supplied by the house. I want to move it down to where the church is supplied by the pump. And use check valves to isolate the two systems. Why am I getting all this feed back? If I've made a bad call about this and my reasoning's faulty then someone please tell me where I went wrong. Tom

What am I missing here guys? Ya-all seem to think that leaving the church takeoff ahead of everything else would be just peachy keen if only you installed a check valve. That's not gonna fly. The plumber refused to install a bladdrer tank in the church, Growler gave you the reason for it and what else do you need? The way it's set up now the church is being supplied by the house. I want to move it down to where the church is supplied by the pump. and use check valves to isolate the two systems. Why am I getting all this feed back? If I've made a bad call about this and my reasoning's faulty then someone please tell me where I went wrong. Tom

I've pulled out and replaced well pumps that had the impellers blown right out of 'em from the shock of the water bouncing back and forth between two bladder tanks -- You also can find bits and pieces of the swing gates from check valves lodged in the well pump or the seat of gate valves -- Once the water starts bouncing back and forth, there isn't anything to stop it from picking up further momentum until something is opened up or something bursts.
Thanks Steve.

Not trying to be argumentative, but for the sake of clarity:

1. How can pressure bounce between two tanks that are separated by two checkvalves?

2. What difference does it make where you branch off to the church/house? One way or the other, the two systems are still going to be connected.

3. Since the system is presently: well... tank... UV unit... split to house/church, then why not simply put a tank in the church with a check valve to prevent water from flowing backwards? That would seem to be a fairly inexpensive and simple solution.

4. My big question, still unanswered: How do you control two pressure tanks, separated from each other by check valves, and only one pump? Can this be done with two switches?

I know that's a lot of questions. Ignore them if you'd like to, but I'd really like to know about #4. However, if the UV unit is really needed, then SB's solution would call for a second unit at the church. Again, not trying to provoke anything, but the homeowner would need to be aware of that.

Not trying to be argumentative, but for the sake of clarity:

1. How can pressure bounce between two tanks that are separated by two checkvalves?


The check valves would never actually be closed -- The ping-ponging effect would leave the gate of the check valves fluttering back and forth, most often in a partially open position.

If this were a system I was designing, I would put a storage tank with a ballcock assembly and booster tank in one or the other of the dwellings and remove it from the pressure tank.

First, my question of "What's wrong with my logic" was a real question. Not arguing for a position. While I've had some exposure and experience to well systems I'm certainly not in a position to argue about anything. While my logic makes sense to me (but then it always does, no matter how wrong I am), I realize that there is too much I don't know. Therefore I was really was asking where am I wrong, what am I missing.

With all that in mind, I'd like to ask another question. I'm not being argumentative here. While I can grasp the idea of cavitation, back pressures, reactions to pressures changes, pump surges, I don't know under what circumstances they occur.

So here goes the question. I can see how cavitation could occur, due to pump surges, if the pump is feeding two tanks . Two tanks shall we say in parallel. But do you have that problem if the tanks are in a series? One tank feeding the other. It seem to me that two tank in a series would act like one larger tank for the most part.

Remember it is a question, and only a question. Also, keep in mind that I only have one brain cell and its showing it's mileage.

For the sake of discussion, as to Ron's question about pump control. A pressure switch on the first tank, since its pressure would always be less than or equal to the second tank, assuming a check valve. Without a check valve with positive seal the tanks would always have equal pressure.

So here goes the question. I can see how cavitation could occur, due to pump surges, if the pump is feeding two tanks . Two tanks shall we say in parallel. But do you have that problem if the tanks are in a series? One tank feeding the other. It seem to me that two tank in a series would act like one larger tank for the most part.

Remember it is question, only a question. Also, keep in mind that I only have one brain cell and its showing it's mileage.

We are talking about bladder tanks, right?

Two pressurized bladder tanks will always be fighting for supremacy, even a 1/2 pound difference in pre-charge can start a ping-ponging cascade.

Two pressurized bladder tanks will always be fighting for supremacy

Maybe that's what I'm missing. Can you explain or tell me why?

I'm not following that either. Again, not to be argumentative. I think HK is suggesting that the tank with the higher pressure would not seem to be in a position to "bother" the other tank as the checkvalve should not allow that to happen. But I am also not in a position to argue it and the guy with the experience is saying it will happen, regardless of checkvalves.

Wid, when you say, "If this were a system I was designing, I would put a storage tank with a ballcock assembly and booster tank in one or the other of the dwellings", are you referring to a booster pump?

OK guys, Would this work? Disconnect the ultra violet unit and the house bladder tank.
Now install a large bladder tank and the ultra violet unit just upstream from the pump. Install two check valves upstream fron the UV and bladder tank, One for each service. We now have one pump, UV unit and a bladder/pressure tank supplying two separate and isolated systems. No conflict between two bladder tanks and Ron, I even included the UV unit you were so concerned about. Steve, (widdershins) does that work for you? Tom

I'm not concerned about the UV unit. They are using it, so I am assuming they have some need for it, which would make them concerned about it.

I have never heard of Steve's concern about pressure "pulses" between two tanks, even though there are checkvalves in place. However, he seems to have some pretty valid experience to back that up. Other than that, SB's idea would seem to be pretty good. One main tank would be controlled by one switch and would simply feed the other two tanks. I'm not sure why you would need to disconnect anything. You are suggesting: pump to tank to UV unit to church/house, which is already what they have. So, I'm not clear on the need to move everything just to get it all a little closer to the pump.

Now, the homeowner no longer seems to be following this thread, so we seem to be having an academic discussion of this. I enjoy reading what you guys have to say about it.

One main tank would be controlled by one switch and would simply feed the other two tanks. not quite what I suggested. What I said was, "install a large bladder tank and the ultra violet unit just upstream from the pump. Install two check valves upstream fron the UV and bladder tank, One for each service. We now have one pump, UV unit and a bladder/pressure tank supplying two separate and isolated systems. No conflict between two bladder tanks.

You are suggesting: pump to tank to UV unit to church/house, which is already what they have And this time you're bang on! The only difference being that they would increase the size of the bladder tank to accommodate the draw on both buildings and a check valve on each service to isolate both systems. The way they have it now is one system serving both buildings. I want to make it into one pump, bladder/pressure tank and the UV unit serving both systems which then supply the house and church. I'm not a pump guy so I need opinions and criticisms . In my area it's a separate trade but every once in a while we're forced to check out a pump simply because we're on site. But common sense should prevail here. If Widdershins says the two tanks will "ping-pong" back and forth thus causing the check valves to flutter then I believe him. So let's get by with one large tank for both units. Comments?? Tom

Yes, we seem to have lost Waterboy. I'd still like to know if this occurs all the time or just when the pressure is at the low end of the scale. We don't even know what pressures the pump is operating at. Could be as low as 20-40. Also like to know pipe sizes where church is tied in. The pressure (and the flow) could be so low that all the water would simply rather go to church than go upstairs.

Yes, we seem to have lost Waterboy. I'd still like to know if this occurs all the time or just when the pressure is at the low end of the scale. We don't even know what pressures the pump is operating at. Could be as low as 20-40. Also like to know pipe sizes where church is tied in. The pressure (and the flow) could be so low that all the water would simply rather go to church than go upstairs.

I can see losing volume at the uppermost terminal, even in a closed pressurized system, but losing pressure is an altogether matter.

It would be interesting to find out what the distance is between the two dwellings -- Not 'as the crow flies' distance, but actual linear feet.

Also, the more I think about this, the more I wonder if pressure isn't being bled off in a worn ballcock or dripping faucet in a lower WC in the Church.

Seventy five (75) from house to church, but we don't know anything about pipe sizes. Well is 160 from house. We don't know anything about pressure settings or pump volume. We really don't know enough about when it happens. Could be it only happens when running on pump only. Pump might be delivering only 1 or 2 gallons per minute.

Any comments on my solution? If I'm wrong somewhere I'd like to know where. AMHD is a learning precess for me in some areas, especially about the newer stuff,
So if I've made a error I'd be happy if someone pointed it out. Regards, Tom

Your solution sounds good to me, although I think it might be one tank too many. I think I would tend to simply run the house off the large tank and feed a second tank, separated by a checkvalve as you have indicated. But then that would be the very solution that the homeowner's plumber rejected to begin with, so you might be 100% on target.

I think it might be one tank too many.
I suggested one large bladder/pressure tank fro both buildings.

they would increase the size of the bladder tank to accommodate the draw on both buildings and a check valve on each service to isolate both systems. The way they have it now is one system serving both buildings. I want to make it into one pump, bladder/pressure tank and the UV unit serving both systems which then supply the house and church. This is not the set up the plumber rejected.
His objection was using two tanks on the same system. Regards , Tom

"I suggested one large bladder/pressure tank for both buildings." True, but since there are two checkvalves after the large tank, I assumed you had an additional tank in the house as well as a third in the church. Otherwise, two checkvalves would not be needed. Perhaps I misunderstood.

My point is simply this: If indeed you are suggesting a large tank to feed into two smaller tanks, why not just feed into one smaller tank at the church and let the large tank feed the house?

What I said about the plumber originally not liking an idea, I was referring to my idea of two tanks, not your idea of three.

I don't know where you get the idea that I'm suggesting three or even two tanks. I've repeated said, "I suggested one large bladder/pressure tank fro both buildings.
they would increase the size of the bladder tank to accommodate the draw on both buildings and a check valve on each service to isolate both systems. The way they have it now is one system serving both buildings. I want to make it into one pump, bladder/pressure tank and the UV unit serving both systems which then supply the house and church."
Regards, Tom

"Now install a large bladder tank and the ultra violet unit just upstream from the pump. Install two check valves upstream fron the UV and bladder tank, One for each service. We now have one pump, UV unit and a bladder/pressure tank supplying two separate and isolated systems."

That's the part (bold) I'm not getting. If there is only one pressure tank, what is the point of check valves? There would obviously be one between the tank and the well, but why would you need checkvalves between the tank and the house/church if there are no tanks in the house or the church? What kind of backflow would the checkvalves be preventing?

I actually think your proposal is the most simple and common-sense idea, but I'm puzzled at the need for multiple checkvalves. The person's original problem was this: "When a toilet in the church is flushed, the pressure in the second floor bathroom of the house drops to near zero." How will your checkvalves and isolated systems prevent that? When the toilet is flushed, the pressure on the second floor will, it seems to me, drop just as it did before. A hundred checkvalves will not prevent that.

Somehow I must be doing something wrong here because I'm not getting my point across. I don't know! I've laid it out for you so many times that the last few I've just coppied and pasted what I had posted earilier.
Let me give it one more shot.
Materials= One pump and control, one large bladder/pressure tank, a UV Unit if desired and two check valves.
Disconnect the house bladder tank and UV Unit. You'll have the pump pressuring the new tank up to the desired PSI which will be contained in the bladder/pressure tank by the check valves until a draw is made from the house or the church. You now have two systems, (the house and the church) being supplied by the pump and the pressure maintained by the tank. Someone in the church flushes the john and the ballcock begins to fill opening up the check valve supplying the fill water. Toilet tank's filled, ballcock shuts down and the check valve closes. Now someone in the house takes a long shower. The house check valve opens up to supply the water, but the large draw takes the pressure down to where the pump kicks in to bring the pressure bach up to the cut off point. Shower's over and the house check valve closes to bring us backto the starting point. We now have the pump shut off and pressure in the tank just waiting for a draw from either system. That's my solution. I'll now take your concerns one by one.
1)
What kind of backflow would the checkvalves be preventing?
The check valves are there to isolate the two systems. (I think this is where I lost you) They aren't there to prevent backflow from either the house or the church. They are there to contain the pressure in the large bladder/pressure tank until a draw is made by either system. One pump and pressure tank feeding two systems.
2)
My point is simply this: If indeed you are suggesting a large tank to feed into two smaller tanks, why not just feed into one smaller tank at the church and let the large tank feed the house? Forget the two maller tanks already! I don't know where you got that idea I was using more then just one large tank.
3)
The person's original problem was this: "When a toilet in the church is flushed, the pressure in the second floor bathroom of the house drops to near zero." How will your checkvalves and isolated systems prevent that? When the toilet is flushed, the pressure on the second floor will, it seems to me, drop just as it did before. A hundred checkvalves will not prevent that.
The reason you had a pressure fluctuation was because the house and the church were all on one system. By isolating the systems wth check valves flushing a toilet in the church wouldn't affect the house system. Things a bit clearer now? Rrgards, Tom

Yes. I think it's clear... we don't agree. Here's why.

A toilet is flushed in the church, so water begins flowing through check valve #1. A faucet is opened on the second floor of the house just seconds later. Check valve #2 opens to supply water to the second floor faucet, so the systems are now as UNisolated as it gets. So, with both check valves open, and the two systems connected just as though there were no checkvalves (since they are both open), the draw of the toilet reduces pressure to the point that the second floor faucet now gets greatly reduced volume. Won't the man will have the same problem he described in his first post. As far as I am aware, the only purpose of a check valve is to prevent backflow. Putting checkvalves between the tank and the house, then between the tank and the church, will not contain pressure in the tank at all. IF you don't believe that, then try flushing the toilet in the church. What happens? The valve opens and water flows. Turn on the second floor faucet. What happens? Water flows through the check valve. The only valve to contain pressure in the tank is the one between the tank and pump. How? It will not allow water to flow back to the pump under any circumstances. From what you have posted so far, I don't think you will have improved the situation.

Now, you asked for comments, so I have stated mine. I could be wrong, always open to that chance. But you need to explain how the two checkvalves will improve the second floor pressure when BOTH the church and the second floor are using water at the same time.

BTW, you stated, "They are there to contain the pressure in the large bladder/pressure tank". Contain the pressure against what? It just seems to me that if no demand is made for water, the checkvalves serve no purpose since water would not flow anyway. Then, if water is drawn, the valve opens and behaves as though it's not even there. Either way, you could remove the checkvalve and never notice it. And when both the house and the church need water, both valves will be open, and therefore be no more functional than a pipe. They only come into play when water try's to flow backwards. They "check" the backflow. Now, I'm open to seeing where I'm wrong, but again, you need to explain how your two valves improve matters when BOTH the church and the house are using water at the same time.

One thought. Would it profit the man to put a PRV valve on both systems? That way you could limit the pressure to the church. Even when both the house and the church needed water, the church water use would not deplete pressure so much. I say that because it seems to me that what you are describing sounds more like something to limit pressure to the church. The checkvalve, so far as I know, will not do that. It simply opens in response to demand, and then closes with no demand or to stop backflow. I'm not real familiar with the PRVs, but limiting pressure to the church might leave sufficient system pressure to give a better flow to the second floor. Maybe??

you need to explain how the two checkvalves will improve the second floor pressure when BOTH the church and the second floor are using water at the same time. Good question! Have you ever seen two or three houses bring fed off one pump? Increasing the size of the pressure tank acts as a storage tank for both units. Did you think that flushing a toilet in the church and taking a bath in the house would draw down a 80 or 100 gallon pressure tank so it would run out of water especially when the pump kicks in to replace the pressure loss?

Putting checkvalves between the tank and the house, then between the tank and the church, will not contain pressure in the tank at all. Are you thinking I meant anything else then teeing off the pressure tank into two check valves?
Check valves don't contain pressure, huh? Whadda you call that thing located just downstream from the pump that stops the pressure from bleeding back into the well if not a check valve? Works both ways you know. That's what check valves do.
OK! Now let's have your solution. It's been fun but I'm kicking back. See you in the morning. Have a good one. Tom

Come on, SB. We both know that the size of the tank is not this man's problem. Read his post. He stated, "When a toilet in the church is flushed, the pressure in the second floor bathroom of the house drops to near zero". Are you suggesting that the toilet being flushed is running the tank out of water? He could have a million gallon tank and the problem would still be there.

"Whadda ya call that thing located just downstream from the pump that stops the pressure from bleeding back into the well if not a check valve? Works both ways ya know." I call that thing a checkvalve, and as I stated earlier, it does its job by being a one way gate, just like all checkvalves. It prevents water from flowing back to the well. That is all your two checkvalves will ever do in this system... prevent backflow.

SB, I always hold my breath when I disagree with you. I'll be the first person to admit that you have forgotten more about plumbing than I'll ever know. However, in this case I am 100% convinced you are wrong. So, I'll ask you again. When both the house and the church are using water, how do your two checkvalves improve the man's situation? I asked that question above, and your reply concerned the size of the tank, not the function of the two checkvalves.

As to my solution, I'd at least consider the PRV to the church. If the church is even slightly downhill from the house, then the second floor can present a 8 or 12# pound pressure differential relative to the church. If the tank averages 40#, and considering the pressure loss on the system when the toilet is flushed, then I can well imagine the second floor being a problem. Which is why, of course, everyone first jumped on the idea of a second tank for the church.

I'm beginning to believe you're yanking my chain! Have a good night. See you tomorrow.

Damm but I hate to eat crow for breakfast! I'm setting in my recliner at midnight following the two buildiong layout in my head and suddenly it hit me. Geeze! Jlisenbe's right! They don't make a check valve that will contain pressure and then open up when a draw's being made. Looked good in my head, (maybe bI oughtta it examined) when I laid it out. But I was a foreman and if I think I'm right I don't back down from anybody. But when you're wrong you're wrong! And I was wrong!
Yeah! I was jerking your chain a bit in one of my posts but you stuck to your guns and I admire that. My way would have worked so neat if only they made a check valve that contained pressure and then opened to allow a draw.
So I owe you a apology for busting yo chops over this. One more time. You were right and I was wrong and I really hate to start the day out like this. Like I confessed in a earlier post, "I'm no pump guy and my arguments just proved it!
Sorry jlisenbe! Next time I'll engage brain before I engage keyboard. Tom

Gosh, you sure get up early! All I can say is this is my 1 time in thousand to disagree with you and be right. I have a funny feeling I better appreciate this one because it will be a lllooonnnnggggg time before it happens again.

What do you think about using a PRV on the church? Other than putting pressure tanks behind your checkvalves, which the other guy said would create a new set of problems, I can think of no other answer.

Of course, I still don't understand the "ping-pong" thing. I would think the large tank would basically act like a pump to supply water to the two smaller tanks and the two checkvalves would prevent oscillations. But, maybe not. The other guy seemed pretty certain.

I don't know why a PRV valve would help. I like the idea of one large pressure/bladder tank feeding two smaller bladder tanks with the check valves installed to contain the pressure in each of the smaller tanks. Once all the tanks are up to pressure and the check valves closed to prevent backflow from the smaller tanks back into the pump system when the pressure's drawn off from the smaller tank the pressure from the pump tank would force the check valve open and pressurize the smaller tank with then pressure equalized the spring loaded check valve would close to contain the pressure in the smaller tank if a draw were \made in the other system. With both smaller tanks isolated from the larger one by spring loaded check valves and the pressure equal in all tanks I fail to see how any "ping-ponging" could occur. But since I've already flaunted my ignorance on this thread perhaps I'd better just shut up. As I've said, pomps are a separate trade in my area and about the nonly time we get to work on them is if we're repairing something else and the OP asks us to check it out. It's the same for gas in my arrea. All of our water heaters are electric and the last time I piped for gas is when I did a shopping mall that had a bakery in it.
So whadda you think? Pump and large pressure/bladder tank, two spring loaded check valves installed feeding two smaller bladder tanks I'm the house and church.
Works for you? Cheers, Tom, and any time you see me make a bad call you come down on me with a correction. Thanks to you and everyone else on this page that's "backstopping" me.

I kind of like the PRV idea on the church line. Set low it would give preference to the house.

Harold,
Why cut the pressure going to the church and sen increased pressure to the house.
What am I missing?: Tom

If there is inadequate pressure and volume to satisfy both the church and the second story house bath, it seems like reducing the pressure (therefore the volume) to the church would would insure the pressure and volume to upstairs bath at the house.
We still don't know pipe sizes. Almost be willing to bet that the church line is 1" tied into a 3/4" line out of tank.

HK, I have been thinking the same thing about pipe size. Something has to be done to give the second floor a pressure advantage. That's what I thought about the PRV. I imagine a booster pump for the house would do the same thing.

Now I'm wondering if its wall hung toilet with a flushometer valve in the church. Wish the asker would have come back so we could clear this up. If it's a regular toilet, it shouldn't consume any more water than when a sink faucet is on. So I wonder if the upstairs bath has low pressure when a faucet in the church is running. If flushometer, you wouldn't be able to set a pressure reducing valve to low, or it wouldn't operater correctly.(unless they had a low pressure flushometer). Im just board, so I thought id add a little fuel. Lee.

Me too Lee. Wonder what has happened with the guy that drop the pump down the well.

You, id like to know how things worked out there too.

What is the pipe size between the tank and the point where the church is tied in, what is the house pipe size after that point and what is the pipe size to the church.

Pipe sizes: All measurements are diameter. From the well across the basement, 1 1/4" flexable hose, to a coupler to 1 1/2" junction with a well switch and gage (read 36 psi at time of measurement). Left from junction to a coupler to a 1 3/4" pipe to pressure tank. Right from junction to 7/8" pipe to filter, sterilizer, water softener (all 7/8"), to junction, 7/8" to church and 1" to house. Off the 1", a junction to 7/8" pipe to water heater.

I still suspect that the cheapest, easiest thing to at least try first is put a PRV valve on the church to prevent it from causing such a pressure drop when a toilet is flushed. Set the valve to 30# and see if it allows enough residual pressure for the house to help with your problem. But I suspect there will always be a pressure drop on the second floor when the church uses water. Thus is the world of well water.

I'd also try bypassing the UV unit just to be sure it is not restricting flow. Again, it's a cheap, easy first thing to try.

Thanks for all the advise. We're putting it all together to decide whaat the best solution will be.

Just hit me... a 7/8" pipe? I've never heard of one. Am I missing something here? Is this an inside vs. outside diameter thing?

Please help me with this! I built a minihome next to my 185 year old homestead. The well is fantastic at the old house (80 plus feet deep of pure, clean good water); the water at the minihome is VERY poor-full of minerals and continually discolours. Can I run a line from one well to the other? We share a driveway!

Assuming the minihome is fairly close to the good well, you can certainly run a 1" line to the minihome. However, you might want to add a second pressure tank (or a larger one) at the well to have a higher reserve.